There's been a huge post 'bout kuhlis AND NO ONE TOLD ME!?
Kuhlis are known to lay one their sides, giving the impression they are dead, dying, or ill. It's just how they are, they're lazy little bums who are to lazy to roll back up if they lean over.
They are also known to find the weirdest place in the tank and hang on it like a piece of party tape or TP in a tree...Here are some examples: